Cytopathological and chemico-physical analyses of smears of mucosa surrounding oral piercing.

OBJECTIVE: The aim of this comparative study was to analyze cytopathologically and chemico-physically the mucosa surrounding oral piercing to correlate results with adverse tissue signs. MATERIALS AND METHODS: The tongue superficial mucosa of 15 young subjects (control group) and the superficial mucosa surrounding oral piercing of 15 young subjects (test group, TG) were smeared on slides, Papanicolaou stained and analyzed under the optical microscope. Some smears were prepared for (back-scattered) scanning electron microscope (SEM) and X-ray microanalysis to study piercing fragments. RESULTS: Smears of TG displayed a variable extent of bacterial cytolysis of epithelial cells, fungi, hyperkeratosis, parakeratosis, granulocyte infiltration, calcium formations and bacterial flora; the four last statistically significant (P < 0.05). Foreign bodies surrounded by keratinocytes were detected under both light and SEM. X-ray microanalyses highlighted piercing alloy aggression, ion release and an inverse gradient of ion concentration inside keratinocytes. CONCLUSIONS: The pathological findings in smears correlated with adverse effects of oral piercing. Ion release may be related to direct toxic effects and belated reactions because of metal sensitization. A strict regulation of piercing is warranted.

Histological study on sinus lift grafting by Fisiograft and Bio-Oss.

The work aims to provide a histological investigation of Fisiograft, a PLA/PGA copolymer, used as filler for bone defects in humans. The study was performed on biopsies of sinus lifts where Bio-Oss and Fisiograft gel were applied as graft material. Bone regeneration was satisfactory in all sinus lifts, even when Fisiograft was applied alone. Due to remarkable osteoclast activity, Bio-Oss granules were cleared from the majority of biopsy cores. At histology, Fisiograft gel appeared as globes enveloped by fibroblasts, displaying an epithelial-like cell appearance. Due to its solubility in solvents, undegraded Fisiograft (recorded for 7 months or more) did not stain whereas degraded Fisiograft stained positive. The loose connective tissue, that surrounded Fisiograft and bone contained isolated mastocytes. Bone grew inside the loose connective and often reached the surface of Fisiograft by intervening cells. The results seem to indicate that Fisiograft may be considered both a polymer useful for fastening bone substitutes inside a defect and in addition a material capable of prompting bone regeneration, with or without the use of a bone substitute. In addition to space-former and space-maintainer functions, Fisiograft shows potential bone stimulation function, which may be labelled as osteopromotive capability.

Release of elements from retrieved maxillofacial plates and screws.

Vitallium appliances and surrounding tissues were investigated to evaluate the release and accumulation of elements. Four microplates, sixteen screws and surrounding tissues were removed from three patients presenting inflammation 4 to 6 years after surgery and were submitted to SEM and X-ray microprobe analysis. Histology was performed on paraffin or PMMA sections of tissues.A continuous release of elements from metallic appliances into soft tissues was observed. Cobalt, chromium, and nickel were detected in soft and boney tissues in close proximity to the appliance. Aluminium, as a component of screw coatings, accumulated in soft tissues, and a remarkable amount of aluminium was detected in the dense lamella of lamellar bone. The results suggest that coatings containing aluminium should be avoided and the time these appliances are allowed to remain in patients should be shortened. Further studies on element release and the fate of aluminium in bone are warranted.

[Metallic elements in tissues surrounding internal rigid fixation (IRF) devices]. / Elementi metallici nei tessuti circondanti dispositivi per fissazione interna rigida (FIR).

BACKGROUND: Plates and other devices made by several alloys have been introduced to reach the stability of bone fractured fragments. Elements constituting alloys could be detected especially in organs, yet also in local tissues. Aim of the present study is the analysis of tissues surrounding IRF devices analyzing the morphology of released particles and studying the behavior of adjacent tissues to check metallic elements diffusion. METHODS: Biopsies were retrieved from 18 patients, aged 20 to 76 years. The patients received IRF by plates, screws and grids from 4 months to 9 years. They were divided into five groups according to the local phlogistic degree. Ordinary light microscopy, scanning electron microscopy and X-ray microprobe analysis (EDS system) was used to perform morphological investigations and identification of metal particles and elements. RESULTS: Metal particles or elements arising from plates, screws or grid may undergo tissular diffusion and cellular uptake. Not only Chromium, Iron or Aluminium but also Titanium may be easily released from devices and engulfed in tissues. In particular Titanium diffusion is evident in fibrous tissue surrounding IRF devices. Aluminium appears to be particularly accumulated in a persistent way in fibrous tissues and shows a characteristic embedding pattern in lamellar bone. CONCLUSIONS: The degree of local phlogosis appears to be strictly correlated to metallosis. Chromium, Iron, Aluminium and also Titanium, even if at different degree, give rise to phlogistic effects. Metallosis and phlogosis can produce a cascade process in which they are both the cause and the effect at the same time. The abundant release of Titanium, which does not normally produce clinical phlogosis as i.e. Aluminium, should be worthy of further investigations on its cellular effects.

[Clinical evaluation, radiologic and histologic analysis in mandibular alveolar distraction procedures. Preliminary study]. / Valutazioni cliniche, analisi radiologiche ed istologiche nelle procedure di distrazione alveolare mandibolare. Studio preliminare.

BACKGROUND: Alveolar distraction osteogenesis is a process to form new alveolar bone to correct alveolar deformities in ridge height and width. Aim of this work is to study the bone processes to optimize the implantoprosthetic rehabilitation. METHODS: Alveolar distraction osteogenesis was applied in 7 patients with ridge deformities to obtain the desired ridge augmentation. Clinical and radiological evaluations were performed during the following 12 weeks, before implant insertion. Biopsies at 40, 60 and 88 days were studied after general, specific and histochemical staining of slides; microradiographs were analyzed to evaluate the trabecular bone volume. RESULTS: Forty days after the end of distraction, soft callus shows the start of ossification. Sixty days after the end of distraction, soft callus was widely converted into a network of trabecular woven bone; osteogenic activities were low; trabecular bone volume was about 50%. Eighty-eight days after the end of distraction bone amount appeared reduced, with a more ordered structure, further reduction of bone formation activity, whereas osteoclast erosion was active. CONCLUSIONS: Results show an almost steady-state bone deposition processes 60 days after the end of distraction and a regress with longer time. The results suggest the possibility of an early implant insertion to avoid bone loss due to mechanical unloading.

Neovascularized bone grafts: experimental investigation.

Vascularized bone grafts are standardized procedures in reconstructive surgery but there are some disadvantages: donor site morbidity, limited number of "natural" donor sites, and complex technique. In this study, we test the possibility of creating a "neovascularized" bone graft utilizing a vascular implantation procedure in a rabbit model. Sixteen New Zealand adult white rabbits were used. In each animal, two iliac crest bone grafts (7 x 7 x 10 mm) were harvested. Vascular implantation of the right superficial femoral vessels was performed in one of the two grafts, which was wrapped in a silicone envelope to avoid neovascularization from the surrounding tissues and positioned in a subcutaneous pocket in the right medial thigh. On the left side, the bone block, wrapped in the silicone envelope, was buried subcutaneously without vascular implantation. The operated animals were divided into two groups: Group I included eight rabbits explanted 4 weeks postoperatively and Group II included eight rabbits explanted 8 weeks postoperatively. Tetracycline injection was performed 72 hours preexplantation to evaluate new bone formation. Selective colloidal ink injection in the axial artery was performed to investigate the neovascularization before inclusion in poly-methyl-methacrylate (PMMA). Histological examination was performed in all explanted specimens comparatively. Histological examination 8 weeks after surgery showed a marked neovascularization, with normal bone cells. Tetracycline labeling showed new bone formation with a normal pattern. In all nonvascularized specimens, no viable cells or neovascularization and no bone formation were found. The vascular implantation procedure can induce a good neovascularization with new bone formation in a small bone graft. The possibility of neovascularization induction by the simple vascular implantation procedure has several clinical implications in reconstructive surgery.

Induction and pharmacological treatment of oral osteopenia in rats.

BACKGROUND: Osteoporosis is a major public health problem, responsible for a great number of fractures, associated with devastating costs to society. In addition, oral bone loss has an enormous impact on the health quality of life of patients, affecting up to 90% of elderly individuals. The aim of this work was to elaborate an animal model of mandibular and maxillary osteoporosis in which to evaluate bone loss and possible prevention by pharmacological treatment. METHODS: Six Sprague-Dawley rats were gonadectomized and treated with clodronate (male) or 17 beta-estradiol (female) for two months. Six gonadectomized and six sham-operated rats of both sexes were treated with placebo. The mandible and maxilla, fixed and methacrylate embedded, were serially sectioned, microradiographed and processed for histomorphometric analysis. RESULTS: Gonadectomy did not modify the amount of compact and trabecular bone in mandibles of rats of either sex, treated or not with clodronate or estrogens, compared to sham-operated rats. Compared to sham-operated rats, a 10-25% increase of bone porosity was found in the maxilla of ovariectomized rats, either receiving estrogens or not, while in male rats no difference among groups could be evidenced. CONCLUSIONS: The conclusion is drawn that rats, due to their peculiar masticatory habits yielding huge loads on oral bones, do not represent a suitable experimental model for studying oral bone loss related to skeletal osteoporosis. In order to worsen oral osteopenia it would be mandatory to combine gonadectomy with a mechanical unloading (i.e. after molar extraction) of mandibular or maxillary bone.

Guided bone regeneration using titanium grids: report of 10 cases.

In order to ensure an adequate space where new bone can be formed in guided bone regeneration (GBR), most surgeons fill bone defects with biomaterials. In this work we evaluated new bone regeneration in 10 patients using only a blood clot protected with titanium grids and non-resorbable membranes, without any filling material. A manual measurement of the size of the bone defect, using a plastic probe, was performed at 2 surgical steps. After 5 months of treatment, a biopsy was taken from each patient, fixed and embedded in PMMA, examined microradiographically and morphologically to evaluate the newly-formed bone. Our results showed a good repair of the defects by bone regeneration (about 85% overall), high mineral density of new bone around the implants after 5 months, and steady state deposition processes. These results in GBR, without filling material, appear very promising for implantology and reconstructive odontostomatology practice.

Effects of essential amino acids and lactose on bony fractures and defects in rabbits: a preliminary histomorphometric study.

An experimental study was performed in order to test the possibility of improving bone repair with the administration of a drug (Calciofix, Farmaceutici Damor SpA, Naples, Italy) containing essential amino acids and lactose. Fifty rabbits were submitted to an open transversal fracture of the left fibula and to a right femoral condyle defect. They were left untreated or treated daily with the drug orally and were divided into subgroups depending on the experimental time: 15, 30, 40, 50, 60 days. Histomorphometric data showed a significantly faster healing rate in treated animals compared with untreated ones. Firstly, on day 30 there was a significantly larger amount of cartilage in the control bone callus (P < 0.01). On day 50 a significant difference existed between trabecular and lacunar percentages in the two subgroups (P < 0.0005). At 60 days no significant differences were observed, but bony trabeculae had become more oriented parallel to the long axis of the bone in treated animals. Secondly, after 15 days the defect area was significantly smaller in treated animals than in the untreated ones (P < 0.01). At 30 and 40 days, respectively, significant differences existed between the two subgroups in connective tissue and mature bone percentages (P < 0.01 and P < 0.001). Our results seem to demonstrate that the drug significantly accelerates the rate of bone formation in fractures and bone defects in rabbits.

Immunohistochemical detection of cell-cycle associated markers on paraffin embedded and formalin fixed needle biopsies of prostate cancer: correlation of p120 protein expression with AgNOR, PCNA/cyclin, Ki-67/MIB1 proliferation-scores and Gleason gradings.

Paraffin embedded and formalin fixed needle biopsies of prostate cancer (PC) were used to immunocytochemically detect the p120 nucleolar protein in relation to the Gleason histological gradings (GHG), the labelling indices of proliferating nuclear immunocytochemical markers (PCNA/Cyclin, Ki-67/MIB1) and the argyrophilic nucleolar region (AgNOR) rate. The twenty-six cases of PC (6 from large histological samples and 20 from needle biopsies) were equally distributed into low (< or = 6) or high (> or = 7) GHG groups. The p120 nucleolar protein immunocytochemical reaction was randomly expressed in large histological sections but uniformly distributed without gaps in needle biopsy sections. Only on the latter were quantitative values of PCNA/Cyclin (23.2 in low and 45.3 in high GHG), Ki-67/MIB1 (13.8 in low and 43.3 in high GHG) and AgNOR (5.0 in low and 7.5 in high GHG) related to those of p120 nucleolar protein (0.8 in low and 3.8 in high GHG). The values of all these cell cycle markers increased from low to high GHG of PC, all four reaching high statistical significance between the two groups (ANOVA-two tailed p < 0.0001). The PCNA/Cyclin index showed a higher positivity than the Ki-67/MIB1 index in PC with low GHG but not in PC with high GHG. In conclusion, paraffin embedded and formalin fixed PC needle biopsies exhibit a higher diagnostic PCNA/Cyclin than Ki-67/MIB1 index for cases presenting differentiated features, whereas p120 nucleolar protein detection seems to be a suitable marker of poorer outcome of PC.

Morphology of peri-implant regenerated bone, in sheep's tibia, by means of guided tissue regeneration.

BACKGROUND: No data on the resistance to functional loads of bone regenerated by means of guided tissue regeneration, can be found. In this paper the new-formed bone is analyzed, in cases that see the surgical creation of defects in testing animals. The morphological aspects of perimplant bone, regenerated by means of bone substitutes or not, were evaluated. METHODS: A coronal defect was created by means of a counter-sink bur. The following step provided for osseointegrated fixtures, with a machined or blasted (TiOblast) surface, to be installed. Some bone defects were filled with Bio-Oss, and covered with resorbable membrane (Vycril), others were left unfilled. The animals were sacrificed after different periods of time (24 and 45 days). Some thick sections (200 microns) underwent then microradiography and were examined with a microscope, under transmitted and polarized light. Other sections, thin (5 microns), were coloured with toluidine blue, Gomori's Stain and Solochrome Cyanine/Congo red. RESULTS: Data confirm the excellent behaviour of bovine bone and of TiO blasted fixtures. The experimental results bring into evidence that, in cases of Guided Bone Regeneration (GBR) by means of membrane, the use of fixtures with a blasted surface (TiOblast), and of Bio-Oss as bone substitute, made osseointegration easier. CONCLUSIONS: Results, moreover, suggest that in case of implant surgery with GBR, in order to allow the maturation of regenerated bone, it's healing time must be prolonged.

[Osteo-conductive materials: animal experiments and instrumental analysis II]. / Materiali osteoconduttori: sperimentazione animale e analisi strumentali. Nota II.

BACKGROUND: In daily dental surgery practice, when it is not possible to obtain-enough autogenous bone graft to fill bone defects, bone substitutes can be useful for bone regeneration. MATERIALS AND METHODS: After a preliminary microscopic examination of histologic samples obtained from semithin sections of the tibias of rats showing no major differences in the results both for the single material and implant time, further studies on five different osteoconductive materials used in oral clinical practice were carried out with microradiography, SEM and X-ray microanalysis. In experimental animals (rats) bone defects 3 mm large were surgically induced in both tibias: one of the defects was filled by bone substitutes and on the other side the bone defect healed naturally. RESULTS AND CONCLUSIONS: The findings obtained were studied in depth, and allowed to conclude that the materials tested are suitable for the purpose for which they are marketed. Non-demineralized bovine bone showed the best results with a high degree of osteointegration. However, the results also show that not all the materials tested offer healing advantages over controls.

Histomorphological analysis of the effect of rigid fixation on growing sutures in the rabbit.

The effect of internal rigid fixation (IRF) on bone growth was studied in an experimental model set up in the rabbit. The frontonasal suture of the right side was surgically bridged by a microplate. As reference for bone growth, four screws were placed symmetrically in the four bony segments including the frontonasal suture on both sides. The suture development was followed dynamically for 40 days on the basis of the position of the screws established radiographically. The rate of bone formation along the sutural bones was evaluated by means of the tetracycline labelling technique. The structure of the newly formed bone and its degree of mineralization were respectively analysed under polarized light and with microradiography. It was demonstrated that IRF prevents growth of the sutural membrane but not of the osteogenic process; as a consequence the constrained sutures soon undergo synostosis. This fact must be taken into consideration when IRF is employed in children in order to avoid delayed removal of the plate irreversibly stopping the growth of the constrained suture.

In vivo behavior of a high performance duplex stainless steel.

An in vivo investigation of a new high molybdenum and nitrogen duplex stainless steel (25Cr--7Ni--4Mo--0.3N) has been performed. Cylindrical pins and specially developed devices, to test in static conditions the in vivo localized corrosion resistance, made of this new duplex steel and of a common austenitic stainless steel were implanted in rabbit's femurs for 6 and 12 months. After sacrifice, SEM observations and EDS microanalyses to detect metallic ion release were carried out on the femur sections surrounding the pins. Morphologic observations with stereoscope and SEM were performed on the metallic surfaces of the special devices in order to detect the presence of localized corrosion. Both ion release and localized corrosion were observed for the specimens made of austenitic stainless steel, but not for those made of 25Cr--7Ni--4Mo--0.3N duplex stainless steel.

Bioceramics in orthopaedic surgery: state of the art and preliminary results.

Ceramic materials utilized in orthopaedic surgery can be divided into bioinert, causing minimum tissue reaction, and bioactive types, capable of stimulating bone tissue growth, establishing a bond capable of supporting physiological loads. Alumina is a bioinert ceramic which shows excellent mechanical resistance and an extremely low level of wear when given appropriate structural characteristics. It is therefore used to make prosthetic hip components (head and acetabulum), to coat metal prosthetic shafts and to make prostheses for small joints. Among the bioactive ceramics, bioglass, bioglaze and hydroxylapatite are included in the study. At present, bioglass and bioglaze appear interesting, but not sufficiently so as to find a precise niche in orthopaedic surgery. Currently the bioactive ceramic with the most possibilities for use in orthopaedic surgery is hydroxylapatite. The close interfacial bond which is established with bone tissue allows it to be used as a filler for defective bones in various skeletal diseases and as a coating for metal prosthetic substrates.

Behaviour of tricalcium phosphate and hydroxyapatite granules in sheep bone defects.

Granules of hydroxyapatite (HA) and tricalcium phosphate (TCP) were implanted in separate holes drilled in mandibular bone of sheep to check the bone growth and in vivo behaviour of the materials. The experiment was performed in three sheep, killed respectively at 4, 8, 12 month. Samples of bone with the materials were explanted, microradiographed and sectioned to evaluate the interface under optical and electron scanning electron microscope. The hole, left empty as a reference, showed no full repair; whereas 4 month after implantation the TCP granules induce total repair of the hole. HA granules crumbled and no new bone induction was seen even 12 month after implantation.

[Monocrystalline aluminum dental implants in animals: a study of the peri-implant tissue]. / Implantations dentaires en alumine monocrystalline chez l'animal: étude du tissu périmplantaire.

After the extraction of two molars in a dog's jaw, a single crystal alumina screw was implanted. Monthly radiographs were taken and analyzed by means of a video display computer (VDC) to obtain densitometric informations about the interface. After one year implantation, the bone segment containing the prosthesis was fixed in 4% paraformaldehyde, embedded in methacrylate and sectioned by a microtome saw. The results in light microscopy with ordinary and polarized light, in SEM and X-ray microanalysis, show the presence of a thick connective tissue layer interposed between the screw and the bone. The histological findings confirm the results obtained through the VDC analysis of the radiographic images.

Relationship between estrogen receptor concentration and cytomorphometry in breast cancer.

This study aimed to evaluate the relationship between estrogen receptor (ER) concentration and cytomorphometric parameters in breast carcinoma. Primary breast cancer specimens were both imprinted on cytologic slides and submitted to ER determination with a dextran-coated charcoal method. Patients were stratified by ER levels ranging from 0 to greater than or equal to 200 fmol/mg protein. Measurements were performed on cytologic imprint technique smears in five cases from each ER strata, using a computer-assisted tracing device. Nuclear, cytoplasmic, and cellular parameters were measured on 50 cells per case. The cytometric findings were correlated with ER concentrations. A statistically significant correlation between decreasing area (P = 0.011), perimeter (P = 0.015), maximum diameter (P = 0.034), minimum diameter (P = 0.008), and volume (P = 0.01) of nuclei and increasing ER levels was found. With regard to whole cells, the following parameters significantly decreased versus increasing ER levels: area (P = 0.038), perimeter (P = 0.046), minimum diameter (P = 0.011), and volume (P = 0.044). A statistically significant relationship between the decreasing cytoplasmic perimeter (P = 0.025), i.e., nuclear plus cellular perimeter, and increasing ER content was found. Cytoplasmic area and nuclear to cytoplasmic ratio (N/C) did not correlate with the amount of ER. In all classes of different ER concentration, cells and nuclei displayed a regular shape closer to a circle than to an ellipse. The results of the current investigation indicate that tumors with higher ER concentration are composed of smaller cells with smaller nuclei than are tumors with lower ER content.